I like steel strings but don't want to get a new guitar. Is that my only option?
It will permanently ruin the guitars neck. Acoustic guitars have an adjustable metal rod in them called a “Truss Rod” that allows the neck to withstand steel string tension. How about putting on high tension nylon strings ?
Don't EVER put steel strings on a nylon stringed guitar. Steel strings have many times more tension than nylon strings. The bodies on nylon stringed guitars are braced lighter than their steel stringed cousins. If you put steel strings on a guitar designed for nylon, they will belly the top up as well as warp the neck. Since they're attached differently, you'd (luckily) have a hard time even getting steel strings to fit. Enjoy your nylon string guitar for what it is, and if you want to play steel strings, buy a guitar designed for them.
